Washing machine agitator shafts



Aug. 9, 1955 O. J. voss 2,714,809

WASHING MACHINE AGITATOR SHAFTS Filed Feb. 6, 1952 2 Sheets-Sheet l F102. FIGB. FIGI.

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United. States Patent WASHING MACHINE AGITATOR SHAFTS Gtto J. Voss, Normandy, Mo., assignor to The Simmons National Bank, Pine Bluff, Ark., a corporation of the United States, as trustee Application February 6, 1952, Serial No. 270,257

2 Claims. (Cl. 64-1.)

This invention relates generally to washing machine agitator shafts and particularly to shafts which are exposed during operation to the wash water.

in washing machines of the character wherein the agitator shaft is exposed to the action of wash water within a tub during the washing operation, serious problems have been encountered with corrosion of the shaft and consequent discoloration of the laundry. it has heretofore been proposed to plate such shafts, but it has been found practically impossible to accomplish a plating which will resist continued exposure to present-day detergents at any reasonable thickness. Since agitator shafts of the character concerned have their upper ends splined to removably receive the customary agitators, it is important that any plating made upon the agitator shaft be held within relatively close tolerance on the splines which have previously been machined. Otherwise, difficulty is encountered in applying and removing the agitator to and from the splined shaft. While many efforts have been made to achieve satisfactory plating, none to my knowledge has been successful. As an alternative to the plating of the agitator shaft, it has been proposed to form the entire shaft of stainless steel, but this adds very substantially to the cost of the shaft.

The object of the present invention generally stated is to provide an agitator shaft of the character aforesaid which will resist the corrosion influences of present-day detergents and yet be produceable within the limits of tolerance required for ready application of the agitator.

Another object of the invention is to provide an agitator shaft and seal combination which will substantially eliminate leakage from the tub into the transmission mechanism.

Other objects will become apparent to those skilled in the art when the following description is read in connection with the accompanying drawings in which:

Figure l is a plan view of an agitator shaft constructed in accordance with the present invention.

Figure 2 is a longitudinal sectional View of an agitator shaft and adjunct seal constructed in accordance with the present invention.

Figure 3 is an upper end view of the agitator shaft shown in Figures 1 and 2.

Figure 4 is a plan view of an agitator shaft constructed in accordance with another embodiment of the invention.

Figure is a longitudinal sectional view of the upper end portion of the agitator shaft section shown in Figure 4.

In accordance with the present invention, a composite washing machine agitator shaft is provided wherein the portion thereof which is exposed to the Wash water within the tub is formed of a material which is resistant to the corrosive influence of detergents, but the balance thereof is constructed of the usual steel. This may be accomplished by forming the body of the agitator shaft in the usual manner but at reduced diameter in its upper extremities, and then forming a zinc die casting in situ about the reduced upper end portion of the agitator Zjiiflaid Patented Aug. 9, 1955 shaft body, such zinc die casting constituting the splined portion of the shaft and also if desired constituting a part of the seal assembly. In accordance with another embodiment, the splined portion of the agitator shaft and such other increments thereof as are exposed to the wash water are formed of stainless steel and suitably secured in co-axial relationship with the body of an agitator shaft formed in the usual manner of steel.

Referring now to Figures 1-3 inclusive of the drawings, an agitator shaft body 1 is machined from steel in the usual manner insofar as the portions thereof below the tub line are concerned. The upper extremity of the shaft 1 is reduced to a diameter substantially less than the diameter of the customary splined section. In the embodiment shown, the upper extremity of the shaft 1 is reduced at section 2 and further reduced at section 3. Preferably the sections 2 and 3 are serrated, and a zinc spline section 4 cast thereon. The section 4 may be produced in a die casting machine having a mold shaped to conform to the exterior of the spline section and in which the sections 2 and 3 of shaft 1 are arranged so as to constitute a permanent core.

In the embodiment shown, the spline section 4 is provided with an integral apron 5 which extends radially outward from a hub 6 and then downward in co-axial relationship with the shaft 1. The apron 5 thus constitutes the counterpart of the case of a conventional seal which is customarily pressed upon agitator shafts. Seals of this character have heretofore exhibited leakage between the case and the shaft, but in accordance with the present invention where the apron 5 is integral with the spline section i, such leakage is impossible.

Within the apron 5, the several elements of the conventional seal are arranged including a rubber boot 7, a spring 8, a Bakelite washer 9, all arranged to rotate with the agitator shaft and bearing upon a bronze washer 10 which seats within a permanently fixed part of the washing machine structure 11. interposed between the Washer 10 and the fixed part of the washing machine structure is a rubber gasket 12.

In the formation of agitator shafts in accordance with this embodiment of the present invention, it is preferable that the reduced section 2 which defines the lower end of the zinc casting 4 begin at a line 13 located within the portion which will be embraced by rubber boot 7 of the seal. It is also desirable that the reduced section 2 terminate short; i. e., below the portions of the zinc piece 4 which are splined as shown at 14. The further reduced section 3 of the shaft 1, however, extends for a substantial distance radially within the splines 14. With this type of construction, adequate strength is provided by the zinc die casting to transmit the forces from the shaft 1 to the agitator and the laundry. The torsional strength of the zinc tube surrounding the reduced section is thereby sufiicient to transmit the forces involved without failure.

Referring now to Figures 4 and 5 for a further embodiment of the invention, with which the conventional seal is employed, the usual agitator shaft 21 is foreshortened more than in the previous embodiment so as to provide a reduced portion 22 at its upper end. The shoulder 23 dividing the body of shaft 21 from the reduced portion 22 is preferably located so as to be in the region embraced by the rubber boot of the conventional seal, and, consequently, the body portion of shaft 21, which is formed of ordinary steel, is not exposed to the wash water. Extending above the body portion 21 of the shaft, and secured upon the reduced portion 22 thereof, is a stainless steel nipple 24, the exterior of which is splined as shown at 25 to receive the usual agitator. In the embodiment shown, the interior of nipple 24 is hollow, but the lower end portion thereof is machined to an inside diameter to provide a recess 26 of dimensions such as to have a press fit with reduced portion 22 of shaft 21.

The parts 22 and 24 are preferably connected together by silver soldering or brazing. This may be accomplished by providing the reduced portion 22 with an annular groove 27 within which a ring of silver solder is placed before the parts are pressed together. After the parts are pressed together, the assembly may be placed in an induction furnace or other suitable heating device whereby the ring of silver solder 28 is melted and works its way along the interface between the parts to secure them together. Alternatively, the ring of silver solder may be disposed in an annular offset 29 formed in the open lower end of nipple 24. As another alternative, the parts 22 and 24 may be assembled together with a pellet of brazing compound in the opening 26 above portion 22, so that when the parts are heated to a temperature sufficient to melt the brazing compound, the latter will run down along the interface and secure the parts together. The latter alternative, however, requires for best results that the assembly of parts 21 and 24 be held in upright relaiii tionship during the heating operation.

The assembly wherein the lower or body portion of the agitator shaft is made of mild steel, and the upper portion thereof (which is exposed to the wash water) is made of stainless steel, provides an advantageously economical solution to the corrosion problem, which, insofar as it is corrosion resistant is concerned, is an equal of an all-stainless-steel shaft, but the cost of which is materially less than an all-stainless-steel shaft.

From the foregoing description, it should be apparent that the invention accomplishes its objects and provides a composite agitator shaft having a corrosion resistance where corrosion resistance is needed, and, withal, quite economical to construct.

While two embodiments of the invention have been disclosed in detail, it is realized that various modifications thereof which have not been described herein will present themselves to those skilled in the art, without departing from the spirit of the invention. It is to be understood, therefore, that the embodiment herein disclosed has been so disclosed merely to illustrate and not to limit the scope of the invention, save as indicated in the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. A composite shaft for an agitator comprising, an elongate body of steel having a non-circular exterior surface extending from one end thereof for a substantial dis-.

tance axially and therebeyond a circular exterior surface, a part of zinc alloy die cast directly on said non-circular surface of the steel body and interfitting therewith to prevent relative rotational movement between said diecast part and said body, said die-cast part having a noncircular exterior surface for interfitting with a member to be driven in rotation thereby without relative movement thereof, and an integral apron extending outwardly from said die-cast part and in radially spaced axially parallel relation hip with the circular surface of said body.

2. The combination with the shaft set forth in claim 1 of a resilient shaft seal disposed within the space between said apron and said circular surface of said body.

References Cited in the file of this patent UNITED STATES PATENTS 1,291,388 Bright et al. Jan. 14, 1919 1,699,770 Voss et a1 Jan. 22, 1929 1,853,993 Paquette Apr. 12, 1932 1,861,640 McCabe June 7, 1932 1,941,259 Green Dec. 26, 1933 2,090,162 Tighe Aug. 17, 1937 2,095,055 Campbell et al Oct. 5, 1937 2,156,395 Klouman May 2, 1939 2,294,517 Smith Sept; 1, 1942 

